Fighting our own bias

The hardest thing I do as a founder isn't fundraising or hiring. It's changing my mind.

Not tweaking an opinion but doing a full 180 on something I've argued for, built around, and told people I was sure about.

The problem is that my biases don't feel like biases. They feel like experience. So when a good argument shows up against them, I don't reject it outright. I just raise the bar. Evidence that agrees with me only has to be plausible. Evidence against me has to be bulletproof.

Building Senso, I've realized this is exactly how most people treat their money. Most financial mistakes aren't about knowledge. They're about refusing to update a belief once it's settled in.

Four I hear constantly:

"Everyone's making money on this bet. I can't miss this."

FOMO feels like a decision but it's usually the absence of one. The price going up is the whole thesis. If you can't say why you'd own it besides "it's been going up," you're not investing in the asset, you're investing in the mood. And the people posting their wins rarely post when they get out.

"The stock is down 30%. I need to get out before it goes to zero."

Panic selling turns a paper loss into a real one, often right after the worst of it. The useful question isn't "how much have I lost?" but "has the reason I bought this changed, or just the price?"

"Debt is bad. Pay off the mortgage as fast as possible."

Sometimes that's right. But sometimes your rate is low, you have high early repayment fees you're not aware of, you're giving up a lucrative tax benefit, and your emergency buffer is thin. Most people never check, because the rule feels too obviously true to question.

"The tax return is already filed. Too late now."

In many countries you can generally correct a return in your favor for up to several years (4 in Spain). Tax authorities will come back to you if you underpaid. Nobody will come back to you if you overpaid. But that money is still claimable.

Different situations, same pattern; a belief formed once, or a feeling from the last few weeks, overruling the actual numbers. Changing your mind costs some pride. Not changing it costs real money.

That's why Isaac J. Sène Texidó and I are building Senso the way we are. It lays out the full picture so you can decide with the numbers in front of you, instead of the old rule in your head.

Which financial "rule" did you hold onto longest before realizing it didn't fit your situation?